JP2005207906A - Radiation detector and radiographic imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation detector and a radiographic imaging apparatus, capable of easily controlling the temperature by suppressing bedewing. <P>SOLUTION: The radiation detector has arranged a radiation block 20, in contact with a detection surface side provided with the heating part of a flat panel type X-ray detector (FPD) 3 and has a coolant tube 21 passing coolant inside the radiation block 20. Also, a sending fan 24 for sending air into a passage 23 formed between a block cover 22 covering the radiation block 20 and the radiation block 20, and a suction fan 25 sucking sent air are arranged. By providing such fans 24 and 25, bedewing can be suppressed. As a results, the rise and fall of temperature are suppressed and temperature controlling can be facilitated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radiation detector and a radiation imaging apparatus used in the medical field, industrial fields such as non-destructive inspection, RI (Radio isotope) inspection, and optical inspection, and nuclear power field. The present invention relates to technology for managing temperature.

  Conventionally, as a radiation detector, for example, there is a flat panel radiation detector (FPD). This detector has a planar shape, takes in radiation from a detection surface for detecting radiation, generates electric charge, and sends it as an electric signal to the image processing means. More specifically, a radiation detector is constructed by laminating a planar sensitive film on a substrate, and the incident radiation is detected using the sensitive film as a detection surface, and the detected radiation is converted into electric charges. Then, charges are accumulated in the capacitors arranged in a two-dimensional array. The accumulated charge is read by turning on the switching element, and sent to the image processing means as an electric signal.

  However, when imaging is performed using a radiation detector in a radiation imaging apparatus or the like, the temperature of the detector rises during imaging, and imaging accuracy may be distorted. Strict temperature control is required to perform imaging accurately. Therefore, by utilizing the fact that the radiation detector has a planar shape, in order to prevent the temperature from rising, a cooling means represented by a heat radiating block or the like is provided in contact with the surface where the heat generating portion is located, thereby It is conceivable that temperature rise can be prevented and temperature control can be easily performed.

However, in actuality, condensation occurs in the block when the refrigerant passes through the heat dissipation block. Temperature control becomes difficult to control, for example, the temperature drops conversely due to condensation. Therefore, in order to suppress condensation, it is conceivable to send a gas typified by air or the like to the cooling means including the heat dissipation block (for example, see Patent Document 1).
JP 11-329338 A (2nd page)

  However, as shown in FIG. 6, even if air is sent to the cooling means, it is not effective in suppressing condensation. In this case, the heat dissipating block 120 shown in FIG. 6 has a refrigerant pipe 121 through which a refrigerant represented by cooling water, liquid nitrogen or the like passes, and the flat panel radiation detector 103 generates heat (a gate driver, a multiplexer, Each heat dissipating block 120 is disposed in an amplifier or an A / D converter. There are two peripheral circuits related to data reading such as a multiplexer, an amplifier, and an A / D converter, and each peripheral circuit is provided on the left and right as viewed from the paper surface of FIG. On the other hand, there is one peripheral circuit related to gate control, such as a gate driver, which is provided on the back side as viewed from the plane of FIG. Therefore, the heat dissipation block 120 is formed in a so-called “U” shape corresponding to the location of the structure (heat generation portion) that easily generates heat.

  Even if a plurality of fans 122 are provided so as to be surrounded by the heat-dissipating block 120 formed in the “U” shape and air is sent toward the heat-dissipating block 120, the generated heat escapes outside the heat-dissipating block 120. Condensation cannot be completely suppressed by the air sent in.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a radiation detector and a radiation imaging apparatus that can easily control temperature while suppressing condensation.

  In order to achieve such an object, the present invention has the following configuration.

  That is, the invention according to claim 1 is a planar radiation detector for detecting radiation, the cooling means disposed in contact with the surface of the radiation detector having the heat generating portion, and the cooling means are covered. A housing member, an air supply means for sending gas into a passage formed between the cooling means and the housing member, and an intake means for sucking the gas sent into the passage; and the cooling means and the housing member. The air supply means and the air intake means are arranged so as to face each other.

  [Operation / Effect] According to the first aspect of the present invention, the cooling means disposed in contact with the surface of the radiation detector having the heat generating portion suppresses a temperature rise in the heat generating portion. On the other hand, since the casing member covers the cooling means, the generated heat can be collected. In a state where the heat is concentrated, the air supply means sends gas into a passage formed between the cooling means and the casing member, and the intake means sucks the gas sent into the passage. Air can flow into the passage between the cooling means and the housing member by feeding and sucking gas, so that the condensed heat can be released by the gas and condensation generated in the cooling means can be suppressed. As a result, temperature management can be easily performed while suppressing temperature rise and fall.

  According to a third aspect of the present invention, in the radiation detector according to the first or second aspect, the cooling means includes a heat radiation block disposed in contact with a surface of the radiation detector where the heat generating portion is provided. In addition, a refrigerant pipe through which the refrigerant passes is provided.

  [Operation / Effect] According to the invention described in claim 3, the cooling means suppresses the temperature rise in the heat generating portion by allowing the refrigerant to pass through the refrigerant pipe provided in the heat dissipation block.

  According to a fourth aspect of the present invention, there is provided a radiation imaging apparatus comprising a planar radiation detector that detects radiation transmitted through a subject, and performing imaging processing based on the detected radiation to image the subject. The radiation detector is formed between a cooling unit disposed in contact with a surface of the radiation detector having a heat generating portion, a casing member that covers the cooling unit, and the cooling unit and the casing member. The air supply means for sending gas into the passage and the air intake means for sucking the gas sent into the passage, and the air supply means and the air intake means are arranged opposite to each other with the cooling means and the housing member interposed therebetween. It is characterized by doing.

  [Operation / Effect] According to the invention described in claim 4, the radiation detector detects the radiation transmitted through the subject, and the subject is imaged by performing image processing based on the detected radiation. . The cooling means provided in the radiation detecting means suppresses the temperature rise in the heat generating part. On the other hand, the casing member covers the cooling means so that the generated heat is concentrated, the air supply means sends gas into the passage formed between the cooling means and the casing member, and the intake means enters the passage. Suck the gas that was sent in. Air can flow into the passage between the cooling means and the housing member by feeding and sucking gas, so that the condensed heat can be released by the gas and condensation generated in the cooling means can be suppressed. As a result, temperature management can be easily performed while suppressing temperature rise and fall. In addition, since the radiation imaging apparatus includes such a radiation detector, it is possible to suppress an imaging accuracy error due to a change in temperature, and to perform imaging accurately.

  According to a sixth aspect of the present invention, in the radiation imaging apparatus according to the fourth or fifth aspect, the cooling means includes a heat dissipation block disposed in contact with a surface of the radiation detector having a heat generating portion. In addition, a refrigerant pipe through which the refrigerant passes is provided.

  [Operation / Effect] According to the invention described in claim 6, the cooling means suppresses the temperature rise in the heat generating portion by passing the refrigerant through the refrigerant pipe provided in the heat dissipation block.

  In the above-described invention (the invention described in claims 1 and 4), the cooling means is divided into a plurality of parts, and the casing member is divided into the same number as the divided cooling means. Preferably, the air supply means and the air intake means are arranged opposite to each other with the cooling means and the casing member interposed therebetween (inventions according to claims 2 and 5). By disposing in this way, gas can be passed smoothly at the divided locations, and condensation can be further suppressed.

  According to the radiation detector and the radiation imaging apparatus according to the present invention, the cooling means suppresses the temperature rise in the heat generating portion. On the other hand, the casing member covers the cooling means so that the generated heat is concentrated, the air supply means sends gas into the passage formed between the cooling means and the casing member, and the intake means enters the passage. Suck the gas that was sent in. Air can flow into the passage between the cooling means and the housing member by feeding and sucking gas, so that the condensed heat can be released by the gas and condensation generated in the cooling means can be suppressed. As a result, temperature management can be easily performed while suppressing temperature rise and fall.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram of a flat panel X-ray detector and an X-ray diagnostic apparatus according to an embodiment, FIG. 2 is a schematic perspective view of the flat panel X-ray detector, and FIG. 3 is a side view. FIG. 4 is an equivalent circuit of the flat panel X-ray detector in plan view. In this embodiment, a flat panel X-ray detector (hereinafter referred to as “FPD” as appropriate) is taken as an example of the X-ray detector, and an X-ray diagnostic apparatus is taken as an example of the radiation imaging apparatus.

  As shown in FIG. 1, the X-ray diagnostic apparatus according to the present embodiment includes a top plate 1 on which a subject M is placed, an X-ray tube 2 that irradiates the subject M with X-rays, and a subject. FPD3 which detects the X-ray which permeate | transmitted M is provided. The FPD 3 corresponds to the radiation detector in the present invention.

  In addition, the X-ray diagnostic apparatus further includes the top panel control unit 4 that controls the elevation and horizontal movement of the top panel 1, the FPD control unit 5 that controls the scanning of the FPD 3, and the tube voltage and tube current of the X-ray tube 2. Image processing for performing various processing based on an X-ray detection signal output from an X-ray tube control unit 7 having a high voltage generation unit 6 to be generated or an A / D converter 40 (see FIG. 4) described later of the FPD 3 Unit 8, a controller 9 that controls these components, a memory unit 10 that stores processed images, an input unit 11 on which an operator performs input settings, and a monitor 12 that displays processed images Etc.

  The top board control unit 4 horizontally moves the top board 1 to accommodate the subject M up to the imaging position, moves the top and bottom up and horizontally to set the subject M to a desired position, or performs imaging while horizontally moving the subject M. Or performing horizontal control after the completion of imaging and retreating from the imaging position. The FPD control unit 5 performs control related to scanning by moving the FPD 3 horizontally or rotating around the body axis of the subject M. The high voltage generation unit 6 generates a tube voltage and a tube current for irradiating X-rays and applies them to the X-ray tube 2. The X-ray tube control unit 7 moves the X-ray tube 2 horizontally, Control relating to scanning by rotating around the axis of the body axis of M, control of setting of the irradiation field of a collimator (not shown) on the X-ray tube 3 side, and the like are performed. When scanning the X-ray tube 2 or the FPD 3, the X-ray tube 2 and the FPD 3 move while facing each other so that the FPD 3 can detect the X-rays emitted from the X-ray tube 2.

  The controller 9 is configured by a central processing unit (CPU) and the like, and the memory unit 10 is configured by a storage medium represented by ROM (Read-only Memory), RAM (Random-Access Memory), and the like. Yes. The input unit 11 includes a pointing device represented by a mouse, a keyboard, a joystick, a trackball, a touch panel, and the like. In the X-ray diagnostic apparatus, the FPD 3 detects X-rays that have passed through the subject M, and the image processing unit 8 performs image processing based on the detected X-rays, thereby imaging the subject M.

  As shown in FIG. 2, a heat radiation block 20 is disposed in contact with the detection surface side of the FPD 3, and a refrigerant pipe 21 through which a refrigerant typified by cooling water or liquid nitrogen passes inside the heat radiation block 20. have. On the detection surface side of the FPD 3, a gate driver 35, a multiplexer 37, an amplifier 38, and an A / D converter 40, which will be described later, are provided. The A / D converter 8, the gate driver 35, the multiplexer 37, the amplifier 38, and the A / D converter 40 are likely to generate heat due to their structures. The heat dissipating block 20 is arranged in correspondence with the location of the structure (heat generating portion) that easily generates heat. The heat radiation block 20 and the refrigerant pipe 21 correspond to the cooling means in the present invention.

  There are two peripheral circuits related to data reading, such as the multiplexer 37, the amplifier 38, and the A / D converter 40, and the peripheral circuits are provided on the left and right as viewed from the paper of FIG. On the other hand, there is one peripheral circuit related to gate control, such as the gate driver 35, which is provided on the back side as viewed from the plane of FIG. In this embodiment, the heat dissipating block 20 is divided into three parts corresponding to the locations of the peripheral circuits. A housing-like block cover 22 covering each heat radiation block 20 is also divided into three parts, which are the same number as the divided heat radiation blocks 20. The block cover 22 corresponds to the housing member in the present invention.

  A passage 23 is formed between the heat dissipation block 20 and the block cover 22. Three air supply fans 24 for sending air to the passage 23 and three intake fans 25 for sucking the air sent to the passage 23 are provided, and the divided heat dissipation block 20 and the block cover 22 are sandwiched between the air supply fans 24. The fan 24 and the intake fan 25 are disposed to face each other. The air supply fan 24 corresponds to the air supply means in this invention, and the intake fan 25 corresponds to the intake means in this invention.

  In the present embodiment, a circulation type in which the refrigerant circulates in each heat radiation block 20 is adopted. Note that only the refrigerant pipe 21 may be provided across the divided heat dissipation blocks 20, or three refrigerant pipes 21 may be provided independently corresponding to the respective heat dissipation blocks 20.

  As shown in FIG. 3, the FPD 3 includes a glass substrate 31 and a thin film transistor TFT formed on the glass substrate 31. As shown in FIGS. 3 and 4, the thin film transistor TFT has a large number of switching elements 32 (for example, 1024 × 1024) formed in a vertical / horizontal two-dimensional matrix arrangement. The switching elements 32 are formed separately from each other. That is, the FPD 3 is also a two-dimensional array radiation detector.

  As shown in FIG. 3, an X-ray sensitive semiconductor 34 is stacked on the carrier collection electrode 33, and the carrier collection electrode 33 is connected to the source S of the switching element 32 as shown in FIGS. 3 and 4. Has been. A plurality of gate bus lines 36 are connected from the gate driver 35, and each gate bus line 36 is connected to the gate G of the switching element 32. On the other hand, as shown in FIG. 4, a multiplexer 37 that collects charge signals and outputs them to one is connected with a plurality of data bus lines 39 via amplifiers 38, and also shown in FIGS. Thus, each data bus line 39 is connected to the drain D of the switching element 32. The multiplexer 37 is connected to an A / D converter 40 that outputs an X-ray detection signal obtained by converting the charge signal from analog to digital. In FIG. 4, for convenience of illustration, only one peripheral circuit related to data reading such as the multiplexer 37, the amplifier 38, and the A / D converter 40 is shown.

  With the bias voltage applied to the common electrode (not shown), the gate of the switching element 32 is turned on by applying the voltage of the gate bus line 36 (or 0 V), and the carrier collection electrode 33 is on the detection surface side. The charge signal (carrier) converted from the incident X-ray through the X-ray sensitive semiconductor 34 is read out to the data bus line 39 via the source S and drain D of the switching element 32. Until the switching element is turned on, the charge signal is temporarily accumulated and stored in a capacitor (not shown). The charge signals read to the respective data bus lines 39 are amplified by the amplifiers 38 and are collectively output as one charge signal by the multiplexer 37. The output charge signal is digitized by the A / D converter 40 and output as an X-ray detection signal.

  According to the FPD 3 configured as described above, the FPD 3 is disposed in contact with the detection surface on which the heat generating portion (for example, the gate driver 35, the multiplexer 37, the amplifier 38, the A / D converter 40, etc.) is disposed. The radiating block 20 suppresses the temperature rise in the heat generating part by allowing the refrigerant to pass through the refrigerant pipe 21 provided therein. On the other hand, since the block cover 22 covers the heat dissipation block 20, the generated heat can be collected. In a state in which this heat is concentrated, the air supply fan 24 sends air into a passage 23 formed between the heat dissipation block 20 and the block cover 22, and the intake fan 25 sucks air sent into the passage 23. Air can flow in one direction of the arrow in FIG. 2 in the passage 23 between the heat dissipation block 20 and the block cover 22 by air feeding and intake, and the concentrated heat can be released by the air, and the refrigerant passes inside. Thus, the dew condensation generated in the heat dissipation block 20 can be suppressed. As a result, temperature management can be easily performed while suppressing temperature rise and fall.

  In the present embodiment, since the FPD 3 is provided in the X-ray diagnostic apparatus, it is possible to suppress an imaging accuracy error due to a change in temperature and to perform imaging accurately.

  Further, in this embodiment, the heat dissipating block 20 is divided into a plurality (three in this embodiment), and the block cover 22 is divided into the same number as the divided heat dissipating blocks 20, and divided. The air supply fan 24 and the air intake fan 25 are disposed so as to face each other with the heat radiation block 20 and the housing member interposed therebetween. By arrange | positioning in this way, air can be smoothly let through in the divided | segmented location and dew condensation can be suppressed further.

  The present invention is not limited to the above-described embodiment, and can be modified as follows.

  (1) In the above-described embodiment, the X-ray diagnostic apparatus as shown in FIG. 1 has been described as an example. However, the present invention is also applied to an X-ray diagnostic apparatus disposed on a C-type arm, for example. Also good. The present invention may also be applied to an X-ray CT apparatus.

  (2) In the above-described embodiment, the flat panel X-ray detector (FPD) 3 has been described as an example. However, the present invention is applicable to any X-ray detector that generates heat when detecting X-rays. Can be applied.

  (3) In the above-described embodiments, the X-ray detector for detecting X-rays has been described as an example. However, in the present invention, a radioisotope (RI) is administered like an ECT (Emission Computed Tomography) apparatus. As exemplified by a γ-ray detector that detects γ-rays emitted from a subject, any planar radiation detector that detects radiation is not particularly limited. Similarly, the present invention is not particularly limited as long as it is an apparatus that performs imaging by detecting radiation, as exemplified by the ECT apparatus described above.

  (4) In the above-described embodiment, the FPD 3 includes a radiation (in the embodiment, X-ray) sensitive semiconductor and directly converts the incident radiation into a charge signal by the radiation sensitive semiconductor. However, instead of the radiation-sensitive type, it is equipped with a light-sensitive semiconductor and a scintillator, and the incident radiation is converted into light by the scintillator, and the converted light is converted into a charge signal by the light-sensitive semiconductor. It may be an indirect conversion type detector.

  (5) In the above-described embodiment, the heat dissipating block 20 is divided and disposed. However, the form of the disposition is not limited to the form shown in FIG. What is necessary is just to change suitably according to the location of a heat-emitting part. The number to be divided is not particularly limited. Further, as shown in FIG. 5, the heat dissipation block 20 may be formed in a “U” shape without being divided. An air supply fan 24 is disposed at the entrance of the passage 23 and an intake fan 25 is disposed at the exit. However, in view of further smoothing the air and further suppressing dew condensation, it is more preferable to divide and configure as in the above-described embodiment.

  (6) In the above-described embodiment, since the heating surface is on the detection surface side, the radiation block 20 and the fan 22 are disposed on the detection surface side. However, when the heating surface is on a surface other than the detection surface side. In this case, the heat dissipation block 20 and the fan 22 may be disposed on the surface.

  (7) In the above-described embodiment, the refrigerant pipe 21 is a circulation type in which the refrigerant circulates in the heat dissipation block 20, but the refrigerant pipe 21 may be a non-circulation type in which the refrigerant that has once flowed through the heat dissipation block 20 does not pass. Good.

  (8) In the above-described embodiment, the air supply fan 24 sends in air, but for example, the air supply fan 24 sends dry air dehumidified, helium (He), neon (Ne), argon (Ar), etc. The insufflation fan 24 may send in an inert gas such as rare gas or nitrogen (N). That is, it is not particularly limited as long as it is a gas that suppresses condensation. When the dry air is sent in, it is preferable to connect the inlet for taking in the air to the passage 22 via a filter for dehumidification and to provide an air supply fan 24 near the filter. In addition, when supplying the inert gas, it is preferable to provide a supply tank for supplying the inert gas so as to be connected to the passage 22 and to provide the air supply fan 24 at the connecting portion.

  (9) In the above-described embodiment, the cooling block according to the present invention is configured by including the heat radiation block 20 and the refrigerant pipe 21 through which the refrigerant passes. However, for example, a Peltier element is used for normal cooling. As long as it can be used, there is no particular limitation.

  (10) In the above-described embodiment, the air flow is always unidirectional between the divided heat dissipation blocks 20 and the block cover 22, as shown in FIG. An air supply fan and an intake fan may be arranged to flow. However, in consideration of smoothly passing air, it is more preferable to unify in one direction. This is because, when unified in one direction as in the embodiment, it is possible to prevent turbulent flow caused by flowing air in the opposite direction and to prevent air stagnation due to turbulent flow.

1 is a block diagram of a flat panel X-ray detector and an X-ray diagnostic apparatus according to an embodiment. It is a schematic perspective view of a flat panel X-ray detector. It is the equivalent circuit of the flat panel type | mold X-ray detector seen from the side. 2 is an equivalent circuit of a flat panel X-ray detector in plan view. It is a schematic perspective view of the flat panel type X-ray detector which concerns on a modification. FIG. 6 is a schematic perspective view of a conventional flat panel X-ray detector in which a fan that suppresses condensation is simply disposed.

Explanation of symbols

3 ... Flat panel X-ray detector (FPD)
20 ... Radiating block 21 ... Refrigerant tube 22 ... Block cover 23 ... Passage 24 ... Air supply fan 25 ... Intake fan M ... Subject

Claims (6)

  A planar radiation detector for detecting radiation, a cooling means disposed in contact with a surface of the radiation detector having a heat generating portion, a casing member covering the cooling means, and a cooling means / housing member An air supply means for sending gas into a passage formed between them, and an air intake means for sucking the gas sent into the passage, and the air supply means and the air intake means are opposed to each other with the cooling means and the housing member interposed therebetween. The radiation detector is characterized by being arranged as described above.   2. The radiation detector according to claim 1, wherein the cooling means is divided into a plurality of parts and the housing member is divided into the same number as the divided cooling means. The radiation detector is characterized in that the air supply means and the air intake means are disposed opposite to each other with the housing member and the housing member interposed therebetween.   3. The radiation detector according to claim 1, wherein the cooling means includes a heat radiation block disposed in contact with a surface of the radiation detector having a heat generating portion, and a refrigerant pipe through which a refrigerant passes. A radiation detector characterized by that.   A radiation imaging apparatus that includes a planar radiation detector that detects radiation that has passed through a subject and that performs image processing based on the detected radiation and that images the subject. A cooling means disposed in contact with a surface having the heat generating portion of the detector, a casing member covering the cooling means, an air supply means for sending gas into a passage formed between the cooling means and the casing member, A radiation imaging apparatus comprising: an intake means for sucking the gas sent into the passage; and the air supply means and the intake means are arranged to face each other with the cooling means and the housing member interposed therebetween.   5. The radiation imaging apparatus according to claim 4, wherein the cooling means is divided into a plurality of parts and the housing member is divided into the same number as the divided cooling means. A radiation imaging apparatus, wherein the air supply means and the air intake means are arranged to face each other with a housing and a housing member interposed therebetween. 6. The radiation imaging apparatus according to claim 4, wherein the cooling means includes a heat radiation block disposed in contact with a surface of the radiation detector where the heat generating portion is provided, and a refrigerant pipe through which the refrigerant passes. A radiation imaging apparatus.

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